This invention is related to an apparatus that is capable of delivering an accurate volume of liquid.
In custom making of paints, an unpigmented resin solution or dispersion is blended with one or more mill bases which contain dispersed pigments, a liquid carrier and a dispersing resin. To achieve a color match of the paint being made to a standard color, accurate amounts of mill bases must be added and often in very small amounts such as 0.5 cc of a mill base such as black mill base. The slightest deviation from the formula results in an off color paint. Therefore, very accurate delivery equipment is required. A typical prior art apparatus which is used for the precision pumping of fluids is shown in Cocks U.S. Pat. No. 4,026,439 issued May 31, 1977 but this apparatus is not accurate since it uses a pneumatic contol system that does not control the pump accurately, liquid activated check valves that do not accurately control flow and an encoder system having relatively large steps that does not allow for the measurement of very small amounts of fluids.
There is a need for an apparatus for making paints that will accurately and consistently meter out exact volumes of fluid.